Apparatus for coating articles



l Feb. 18, 1947. H. OSTERBERG l-:T/lu.V 2,416,211

APPARATUS FOR coATING ARTICLES Filed sept. 15, 1 943 2 sheetssheet 1 Feb. 18, 1947. H.osTERB1-:RG :TAL l APPARATUS FOR COA'TING ARTICLES Filed Slept. 15. 1945 Y 2 Sheets-Sheet 2 w M /f /f l 7 7 n ML. 1 a M A w w x n u eM/4f., W a 2 33 .3

HAR TERBEG P401.

INVENTOR- 005 H5 JN f` ZATTRNY retenes Feb'. is, i947 .liliuiltivi'Usy Fon coA'nNG anfncms narnia osier-berg ne ramiv o. i'iein, annals;

Y., ors, by meinel American Optical Company,-

enti. Southbridge,

Mass., a'volnntary association A Application separaba-15.1943, sefiamdsoans This invention relates to new and inproved apparatus for coating articles and more particularly to new and improved'apparatus for vaporizing the coating material. 1

An obiect 'of the invention is to provide new and `improved apparatus for coating the surfaces of articles wherein the coating material is vaporized in a vacuum and which'will provide more durable, 1

wear resistant coatings.

Another object of the invention is to provide new and improvedl apparatus for coating the surfaces of articles by 'evaporation in a vacuum whereby the rate ofevaporationand the hardness or durability of lthe coating may be more accu-A rately controlled.

Another object offthe invention is to provide ticles at a relatively low temperature and then increasing the speed of said particles by heat and pressure.

Another object of the invention is to provide a y new andimproved means for vaporizing the coating material and for. depositing said vaporized coating material whereinmore durable wear resistant coatings will be obtained.

Other objects and advantages of the invention will be apparent from .the following description taken in connection with the accompanying drawings and it will be understood thatl many changes may be made in the details of construction, arrangement of parts and steps ofthe procnewand improved means for vaporizing the paress without departing from thescope of the invention as expressed inthe accompanying claims. We, therefore, do not wish to be limited to the exact` details of construction,`arrangement 0i parts and steps of the process shown and described as the preferred form has been shown by way of illustration only.

Referring 'to the drawings: Fig. 1 is a side view partlyin section of a coating apparatus embodying the present invention; Fig. 2 is a sectional view taken on lines 2-2 of Fig. 1, 'looking in the direction of the arrows;

Fig. 3 is a` sectional view taken on lines-3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is a sectional view of the vaporizing means shown in Fig. 1 but on an enlarged scale; i Fig.v 5 is a sectional. view taken on line 5-5 of Fig. 4 looking in the direction ofthe arrows;

Fig. Hooking in the direction of the arrows; andv Fig. 'l-is a sectional view taken on linel 1``iv of Fig. 4 looking in the direction of the arrows.

Referring more particularly to the 'drawings wherein similar `reference 'characters designate corresponding parts throughout the .several views, the coating apparatus shown in Fig. 1 comprises a base I on which is positioned the bell jar .or the like2 to form a vacuum` chamber adapted to be evacuated through the opening l which is connected with suitable vacuum chambers not The upright 4 is provided with the supporting ring 5 adaptedto support the article t such as a lens or the like which has the surface thereof to be coated in the direction of the vaporizing apparatus. y

Extending through the basel are the posts 1 and 8 adapted to receive current through the leads 8" and Ill respectively to provide such current to the `vaporizing apparatus.

The vaporizing apparatus comprises the radiation shield "il formed of carbon or graphite or the like with a lining i2 of platinum and within said platinum member I2' and spaced therefrom is the heater vmember i3 which may be' of carbon or the like or as desired might be formed of other suitable material and which has the projectingl portion Il adapted-to receive and support the carbon crucible memberll which member isl adapted .to contain th coating material to be vaporized.`

The crucible member i5 is threadedly connected to the super heater I8 which may also be l -formed of carbon or the like and which has 'the 'narrow portion i1 through which the vaporiz'ed particles are adapted to pass into the super heater 'member I6 winch is provided with the spray `nozzle type header i8 through which the particles pass to reach the space to b coated.

' Surrounding the super heater i0 is the heat-ing' member I9 of carbon or the like and surrounding this member i9 is the platinum lining .2u `for the radiation shield member 2|. I

The shield' 2l and lining 2li hae openingsaligned with the spray nozzle I8. Y

' The heater member I3 is provided with the slot 22 and the heating element is is provided with the slot 23. l

. Current for the heater Il is received-through Fig. 'is a sectional view taken on line 6-8 of 50 the posts 8 and leads 31 and 28 and current for l the super heater is received through the posts 1 and leads 26 and 24.l

The leads 26 and 21 and the ilange portions on the radiationv shield members'II and 2| are vheld together by the screw members 28 and the leads 24 and 25 and opposite flange members on 1 the radiation'shields and 2| are held together ,Y by the screw 28. i

The heating members I3 and I9 are provided It will be noted that the ilanges 36 and 3| on the ends of the heaters I9 land I3 are wedge 3 shaped and adapted to enter wedge shaped open' ings in the leads and held therein in tight engagement as shown ,in Fig. 5 to insure proper current for said heating members.

In use the member I6 and member .'|5 are removed from the vaporizing apparatus as a unit and the member |5vseparated from` the member the parts and then the coating material is placed' in the membei` I5, the parts` again connected and the unit replaced'l in the vaporizing apparatus. i Current is then applied to the heating member I3 suiiicient to vaporize the coating material within the crucible member I5 which vaporized coating 1 material passes through the restricted opening I1 1 and reachesthe superheater memberv I6. The4 l heating member I9 for the superheater I6,is then' raised to a temperature above the temperature. necessary tovaporize the coating material and because of this heat and pressure the vaporized coating material is forced through the spray nozzle I8 and caused to impinge upon the surface to be coated with considerably greater force than otherwise and therefore forms a ywear resistant,

durable coating.

The present apparatus may be employed for the forming of reection reducing coating on the surl faces of light transmitting articles and in such cases the coating material might be magnesium "fluoride, quartz, cryolite, or other suitable material and the device may also be employed for forming reflective coatings on the surfaces of refiectors and in such cases the coating material 1 might be -aluminum or othersuitable material.

It is pointed out that by employing the present l apparatus with lthe superheater being jheated to a temperature vconsiderably above the vaporization point o f the coating material that a pressure is built up inthe superheater which greatly Vinlcreases the speed of the vaporized particles which are forced outwardly therefrom to form the coating with greater durability and adhesion as stated 3 above.

It is also pointed out that by employing the present apparatus the rate of evaporation of the coatingmaterial can be more accurately controlled by controlling the temperature employed for vaporizing said material and this also allo'ws a greater control of the hardness of the ap- I plied coating.

The present apparatus and method 'also allows the speeding up or accelerating of allof the vaporized particles thus providing greater adhesion ofthe particles to the surface and also provides a more durable, wear resistant coating,

I |6 by means of the threaded connection between g From the foregoing it will be seen that we have provided simple, efficient and economical means vand method for obtaining all of thel objects and advantages of the invention. f

Having described our invention, we claim:I 1. In a device of the character described, a vac- `uum chamber, means for supporting in said chamber an article the surface of which is to be coated, means for distilling coating material for application to said surface, a superheating chainber communicating with said distilling means-and through which said vaporized material is dis-` charged fromsaid distilling means into said vacu um. chamber and means for heating said superheating chamber to a] temperature higher than the temperature required to vaporize said coating p material to increase the speed of emission of the vaporized particles.

2. In a device of the character described, a v uum chamber, means for supporting in said chamber an article to be coated, and means in operative relation 'to' said article for supplyingva-y porized coating material to be applied to a surface of said article, said supplying means including a heated crucible communicating with an elongated jhollowrefratory member through which the vaporized material 'is discharged tocoat said-surface, and means for superheating said hollow refractory member to raise the `temperature vof Vaport passing through said member from the crucible.

chamber an article the surface of which is to be coated, a crucible for receiving the material to be vaporized, a superheating-chamber supplied with vaporized material by Way or a tubular connecting member from said crucible and discharging into said vacuum chamber, and means for heating said crucible to vaporize said material therein and for heating said superheating chamber to a sumciently elevated temperature to increase the speed of said vaporized particles.

4. In adevice of the character described, a vac uum chamber, means for supporting in said chamberaan article to be coated, means for distilling the coating material to be lapplied to a surface ofsaid article, a hollow heatirig member surrounding said distilling means, and an elongated hollow chamber surrounded by a superheater, said elongated chamber being supplied with vaporized coating material from said .distilling means and discharging into said vacuum chamber, said elongated chamber being heated to a sufciently elevated temperature to increase the speed of va-v porized particles passing therethrough.

5. In a device of the character described, a vacuum chamber, means for supporting in said chamber an article to be coated, and means in operative relation to said article for supplying vaporized coating material to be applied to a vsurface of said article, said supplying means including a heated crucible communicating with an elongated hollow refractory member through which vaporized material is discharged to coat said surface, said member comprising la superheater -chamber and a vapor inlet passage thereto of relatively restricted diameter, and means for superheating said superheater chamber of said member to raise the temperature of vapors passing through said member from the crucible.

6. In'a device of the character described, a vacuum chamber, means forrsupporting in said chamber an article to be coated, means for distilling the coating material to be applied to a vsurface of 3. In a device of the character described, a vac-, uum chamber, means for supporting in said said article, a, superheating chamber supplied with vaporized coating material from said distilling means, said .superheating chamber including a spray nozzle for discharging superheated vapor from said superheating chamber Vinto said vacuum chamber, and means fory heating said superheating chamber to a snfiiciently elevated temperatnre to increase the speed of vaporized particles received from said distilling means.

7. In a device o f the character described, a vac- 4uum chamber, means for supporting in 'said chamber an article to be coated, means for distilling the coating material to be applied to a surface of said article, a. chimney for discharging vae porized material lfrom said distiliing'means into said vacuum chamber to impinge upon the surface to be coated, heating lmeans co-operating with a portion of said chimney to superheat-I th vapors discharging from lxsaid'distilling means into said vacuum chamber, said chimney being of reduced interior cross-section between said sper- 5 heater portion and said distilling means.

HAROLD OSTERBERG. e PAUL c. HEIJN. l

REFERENCES CITED 10 The following references are of record in the 

